If the number of monsters controlled by the controller of the attack target changes during the Battle Step, a replay is triggered, wherein the attacking player chooses a new attack target without declaring a new attack.

In the anime and manga, when a player declares an attack, the monster literally attacks the attack target. In most cases the weaker monster will just stand still while the other one destroys it, sometimes it will try to fight back, but will obviously lose unless the player somehow makes it stronger. Some attacks are also given names.

In the manga, there are two types of attacks: normal attacks and magical attacks. Magical attacks can only be performed by certain monsters. Even if a monster cannot be destroyed by battle, magical attacks are able to penetrate it.